What are the functions of the Lymphatic System?
- 1. Fluid balance
- 2. Protection from infection
- 3. Absorption of fat
how does the lymphatic system balance fluid in the body?
It serves as a second drainage pathway for fluid and proteins that escape from blood capillaries and are left behind.
How does the lymphatic system protect us from infection?
Lympocytes, a group of white blood cells, live and multiply in this sytem. From here they can attack and destroy foreign organisms.
How does the lymphatic system absorb fat?
The fats that are too big to enter the capillaries in the digestive system are absorbed into the lymphatic system and added to the blood stream when the lymph joins it.
how does the lymphatic system differ from blood circulation?
It si not a complete circuit. It is a one-way system that begins in the tissues and ends when the lymph joins the blood.
Describe lymphatic capillaries.
They are made up of a single layer of epithelial cells, but have larger gaps than do blood capillaries, making them more permeable.
What are lacteals?
Specializes lymphatic capillaries located in the small intestine's lining to absorb digested fats.
What is the cisterna chyli?
It is the first part of the thoracic duct which enlarges to form a cistern or temporary storage pouch.
What is chyle?
The milky fluid that drains from the intestinal lacteals.
the membrane that surrounds the intestines
a congenital condition caused by abnormal development of the lymph vessels
- usually the result of surgey or trauma.
- ie..a mastectomy where lymph nodes are removed
purpose of a lymph node
basically it is a filter and they contain lymphocytes
what are the main groups of lymph nodes?
- 1. cervical nodes
- 2. axillary nodes
- 3. tracheobronchial nodes
- 4. mesenteric nodes
- 5. inguinal nodes--aka. buboes (where bubonic plague got its name)
The main purpose of the spleen?
to filter the blood.
Name the functions of the spleen.
- 1. cleanse the blood by filtration and phagocytosis.
- 2. destroy old, worn-out red blood cells (gives the by-products to the liver)
- 3. produces red blood cells before birth
- 4. serves as a reservoir for blood
Where is the thymus located?
in the superior thorax deep to the sternum
What happens in the thymus?
Certain lymphocytes must mature in the thymus before they can perform their functions (T-Lymphocytes). Thymosin promotes their growth and lypmhoid tissue throughout the body.
What are the locations of the tonsils? And which are the "true" tonsils?
- 1. The pharyngeal tonsils are the most superior and are usually called the adenoids.
- 2. The palantine tonsils are located at each side of the soft palate. (These are the TRUE tonsils.)
- 3. The lingual tonsils are located at the posterior of the tongue.
inflammaton of the lymph vesells that can usually be seen as red streaks along an extremity
inflammation of lymph nodes
swelling or edema caused by obstruction of lymph flow
"disease of the lymph nodes"
Usually an early sign of HIV infection. (virus)
an acute viral infection that that primarily enlarges the cervical nodes during infection
enlargement of the spleen that normally accompanies acute infectious diseases such as scarlet fever, thyphus fever, typhoid fever, and syphilis.
What are the 2 types of malignant lymphoma?
- 1. Hodgkins disease- common in the early 20's amoung men and women and then more commonly in men over 50; early signs are weight loss, fever, night sweats, fatigue, anemia; Clear sign of disease is Reed-Sterberg cells in lymph node biopsy.
- 2. Non-Hodgkins disease- more common than Hodgkins affecting mostly older adults; enlargement of cervical nodes is an early sign; it is more widespread throughout the lymphatic system and thus speads more rapidly; no Reed-Strenberg cells; occurs commonly with HIV infection
what are the 5 reasons infections occur?
- 1. the portal of entry...ie. respiratory tract, digestive system, skin breaks
- 2. the virulence or the organisms power to overcome
- 3. the organisms ability to produce toxins that damage the body
- 4. the dose or number of pathogens that invade the body
- 5. an individual's predisposition to infection
what are the first lines of defense agianst infection?
- 1. the skin is a mechanical barrier.
- 2. the mucous membranes trap foreign material
- 3. body secretions such as tears, perspiration, and saliva
- 4. certain reflexes such as coughing or sneezing, and vomiting or diarrhea
what are the main phagocytic white blood cells?
- neutrophils (granular leukocyte)
- macrophages (agranular leukocyte derived from monocytes)
What is an NK cell?
Natural Killer cells that can recognize body cells with abnormal membranes and destroy them by secreting an enzyme that breaks down the cell membrane of the abnormal cell.
what are the 4 symptoms of an inflammatory reaction?
- 1. heat
- 2. redness
- 3. swelling
- 4. pain
similar to basophills but the cells reside in the tissues
mixture of leukocytes and fluid
mixture of exudate, living and dead white blood cells, pathogens, and destroyed tissue
how does fever boost the immune sytem?
- 1. it stimulates phagocytes
- 2. it increases metabolism
- 3. it decreases certain organism's ability to multiply
what is interferon?
When certains cells are infected with a virus, they release a substance that prevents nearby cells from producing more virus. It interferes with the multiplication and spead of the virus.
How is interferon B used?
It is used to treat multiple sclerosis because it stimulates cells that depress the immune system.
What is innate immunity?
innate immunity is inborn and inherited in a person's genes
What is adaptive immunity?
It developes after birth. It is accquired by natural or artificial means and may be either passive or active.
active, natural, adaptive immunity
contact with a disease
passive, natural, adaptive immunity
the placenta or the mothers milk
active, artificial, adaptive immunity
passive, artificial, adaptive immunity
- any foreign substance that enters the body and causes an immune response.
- It's critical feature is that it stimulates the activity of T or B cells.
what are the four types of T cells?
- 1. cytotoxic cells- they directly destroy foreign cells
- 2. helper T cells- release a substance called interleukins that stimulate other lymphocytes and macrophages.."calling all white blood cells"
- 3. regulatory T cells- suppress the immune sytem to prevent overactivity
- 4. memory T cells- they remember an antigen and start a rapid response if encountered again
How does a helper T cell get to do its' job?
A macrophage eats an antigen and breaks it down. It displays a fragment of the antigen on its surface along with something that the helper cell recognizes as belonging to "self". When the T helper cell binds to this combination, it releases interleukin which stimulates other leukocytes to join the fight.
a substance produced in response to an antigen; also known as immunglobulin or Ig. They are manufactured by B cells.
How do B cells work to produce antibodies?
They have receptors that bind with a specific type of antigen. When exposed, they multiply rapidly and produce large numbers of clone plasma cells. These cells release the antibodies into the bloodstream that they have produced. Some of the clones do not become plasma cells but instead become memory cells, ready to produce antibodies on contact.
What is the antigen-antibody reaction?
the antibody bonds to the antigen that caused its creation and destroy or inactivate it.
overactive immune stem that begins attacking "self"
how does HIV attack the immune system?
It destroys helper T cells that have a receptor (cd4) for the virus. It then uses its RNA to invade the DNA of a cell and reproduce itself.
a cancer of the blood-forming cells in bone marrow
a process where NK cells normally kill all cancer cells as they arise